// SPDX-License-Identifier: GPL-2.0-only
/*
 * AMD Cryptographic Coprocessor (CCP) AES CMAC crypto API support
 *
 * Copyright (C) 2013,2018 Advanced Micro Devices, Inc.
 *
 * Author: Tom Lendacky <thomas.lendacky@amd.com>
 */

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/scatterlist.h>
#include <linux/crypto.h>
#include <crypto/algapi.h>
#include <crypto/aes.h>
#include <crypto/hash.h>
#include <crypto/internal/hash.h>
#include <crypto/scatterwalk.h>

#include "ccp-crypto.h"

static int ccp_aes_cmac_complete(struct crypto_async_request *async_req,
                                 int ret)
{
        struct ahash_request *req = ahash_request_cast(async_req);
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx_dma(req);
        unsigned int digest_size = crypto_ahash_digestsize(tfm);

        if (ret)
                goto e_free;

        if (rctx->hash_rem) {
                /* Save remaining data to buffer */
                unsigned int offset = rctx->nbytes - rctx->hash_rem;

                scatterwalk_map_and_copy(rctx->buf, rctx->src,
                                         offset, rctx->hash_rem, 0);
                rctx->buf_count = rctx->hash_rem;
        } else {
                rctx->buf_count = 0;
        }

        /* Update result area if supplied */
        if (req->result && rctx->final)
                memcpy(req->result, rctx->iv, digest_size);

e_free:
        sg_free_table(&rctx->data_sg);

        return ret;
}

static int ccp_do_cmac_update(struct ahash_request *req, unsigned int nbytes,
                              unsigned int final)
{
        struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
        struct ccp_ctx *ctx = crypto_ahash_ctx_dma(tfm);
        struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx_dma(req);
        struct scatterlist *sg, *cmac_key_sg = NULL;
        unsigned int block_size =
                crypto_tfm_alg_blocksize(crypto_ahash_tfm(tfm));
        unsigned int need_pad, sg_count;
        gfp_t gfp;
        u64 len;
        int ret;

        if (!ctx->u.aes.key_len)
                return -EINVAL;

        if (nbytes)
                rctx->null_msg = 0;

        len = (u64)rctx->buf_count + (u64)nbytes;

        if (!final && (len <= block_size)) {
                scatterwalk_map_and_copy(rctx->buf + rctx->buf_count, req->src,
                                         0, nbytes, 0);
                rctx->buf_count += nbytes;

                return 0;
        }

        rctx->src = req->src;
        rctx->nbytes = nbytes;

        rctx->final = final;
        rctx->hash_rem = final ? 0 : len & (block_size - 1);
        rctx->hash_cnt = len - rctx->hash_rem;
        if (!final && !rctx->hash_rem) {
                /* CCP can't do zero length final, so keep some data around */
                rctx->hash_cnt -= block_size;
                rctx->hash_rem = block_size;
        }

        if (final && (rctx->null_msg || (len & (block_size - 1))))
                need_pad = 1;
        else
                need_pad = 0;

        sg_init_one(&rctx->iv_sg, rctx->iv, sizeof(rctx->iv));

        /* Build the data scatterlist table - allocate enough entries for all
         * possible data pieces (buffer, input data, padding)
         */
        sg_count = (nbytes) ? sg_nents(req->src) + 2 : 2;
        gfp = req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
                GFP_KERNEL : GFP_ATOMIC;
        ret = sg_alloc_table(&rctx->data_sg, sg_count, gfp);
        if (ret)
                return ret;

        sg = NULL;
        if (rctx->buf_count) {
                sg_init_one(&rctx->buf_sg, rctx->buf, rctx->buf_count);
                sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->buf_sg);
                if (!sg) {
                        ret = -EINVAL;
                        goto e_free;
                }
        }

        if (nbytes) {
                sg = ccp_crypto_sg_table_add(&rctx->data_sg, req->src);
                if (!sg) {
                        ret = -EINVAL;
                        goto e_free;
                }
        }

        if (need_pad) {
                int pad_length = block_size - (len & (block_size - 1));

                rctx->hash_cnt += pad_length;

                memset(rctx->pad, 0, sizeof(rctx->pad));
                rctx->pad[0] = 0x80;
                sg_init_one(&rctx->pad_sg, rctx->pad, pad_length);
                sg = ccp_crypto_sg_table_add(&rctx->data_sg, &rctx->pad_sg);
                if (!sg) {
                        ret = -EINVAL;
                        goto e_free;
                }
        }
        if (sg) {
                sg_mark_end(sg);
                sg = rctx->data_sg.sgl;
        }

        /* Initialize the K1/K2 scatterlist */
        if (final)
                cmac_key_sg = (need_pad) ? &ctx->u.aes.k2_sg
                                         : &ctx->u.aes.k1_sg;

        memset(&rctx->cmd, 0, sizeof(rctx->cmd));
        INIT_LIST_HEAD(&rctx->cmd.entry);
        rctx->cmd.engine = CCP_ENGINE_AES;
        rctx->cmd.u.aes.type = ctx->u.aes.type;
        rctx->cmd.u.aes.mode = ctx->u.aes.mode;
        rctx->cmd.u.aes.action = CCP_AES_ACTION_ENCRYPT;
        rctx->cmd.u.aes.key = &ctx->u.aes.key_sg;
        rctx->cmd.u.aes.key_len = ctx->u.aes.key_len;
        rctx->cmd.u.aes.iv = &rctx->iv_sg;
        rctx->cmd.u.aes.iv_len = AES_BLOCK_SIZE;
        rctx->cmd.u.aes.src = sg;
        rctx->cmd.u.aes.src_len = rctx->hash_cnt;
        rctx->cmd.u.aes.dst = NULL;
        rctx->cmd.u.aes.cmac_key = cmac_key_sg;
        rctx->cmd.u.aes.cmac_key_len = ctx->u.aes.kn_len;
        rctx->cmd.u.aes.cmac_final = final;

        ret = ccp_crypto_enqueue_request(&req->base, &rctx->cmd);

        return ret;

e_free:
        sg_free_table(&rctx->data_sg);

        return ret;
}

static int ccp_aes_cmac_init(struct ahash_request *req)
{
        struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx_dma(req);

        memset(rctx, 0, sizeof(*rctx));

        rctx->null_msg = 1;

        return 0;
}

static int ccp_aes_cmac_update(struct ahash_request *req)
{
        return ccp_do_cmac_update(req, req->nbytes, 0);
}

static int ccp_aes_cmac_final(struct ahash_request *req)
{
        return ccp_do_cmac_update(req, 0, 1);
}

static int ccp_aes_cmac_finup(struct ahash_request *req)
{
        return ccp_do_cmac_update(req, req->nbytes, 1);
}

static int ccp_aes_cmac_digest(struct ahash_request *req)
{
        int ret;

        ret = ccp_aes_cmac_init(req);
        if (ret)
                return ret;

        return ccp_aes_cmac_finup(req);
}

static int ccp_aes_cmac_export(struct ahash_request *req, void *out)
{
        struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx_dma(req);
        struct ccp_aes_cmac_exp_ctx state;

        /* Don't let anything leak to 'out' */
        memset(&state, 0, sizeof(state));

        state.null_msg = rctx->null_msg;
        memcpy(state.iv, rctx->iv, sizeof(state.iv));
        state.buf_count = rctx->buf_count;
        memcpy(state.buf, rctx->buf, sizeof(state.buf));

        /* 'out' may not be aligned so memcpy from local variable */
        memcpy(out, &state, sizeof(state));

        return 0;
}

static int ccp_aes_cmac_import(struct ahash_request *req, const void *in)
{
        struct ccp_aes_cmac_req_ctx *rctx = ahash_request_ctx_dma(req);
        struct ccp_aes_cmac_exp_ctx state;

        /* 'in' may not be aligned so memcpy to local variable */
        memcpy(&state, in, sizeof(state));

        memset(rctx, 0, sizeof(*rctx));
        rctx->null_msg = state.null_msg;
        memcpy(rctx->iv, state.iv, sizeof(rctx->iv));
        rctx->buf_count = state.buf_count;
        memcpy(rctx->buf, state.buf, sizeof(rctx->buf));

        return 0;
}

static int ccp_aes_cmac_setkey(struct crypto_ahash *tfm, const u8 *key,
                               unsigned int key_len)
{
        struct ccp_ctx *ctx = crypto_ahash_ctx_dma(tfm);
        struct ccp_crypto_ahash_alg *alg =
                ccp_crypto_ahash_alg(crypto_ahash_tfm(tfm));
        u64 k0_hi, k0_lo, k1_hi, k1_lo, k2_hi, k2_lo;
        u64 rb_hi = 0x00, rb_lo = 0x87;
        struct aes_enckey aes;
        __be64 *gk;
        int ret;

        switch (key_len) {
        case AES_KEYSIZE_128:
                ctx->u.aes.type = CCP_AES_TYPE_128;
                break;
        case AES_KEYSIZE_192:
                ctx->u.aes.type = CCP_AES_TYPE_192;
                break;
        case AES_KEYSIZE_256:
                ctx->u.aes.type = CCP_AES_TYPE_256;
                break;
        default:
                return -EINVAL;
        }
        ctx->u.aes.mode = alg->mode;

        /* Set to zero until complete */
        ctx->u.aes.key_len = 0;

        /* Set the key for the AES cipher used to generate the keys */
        ret = aes_prepareenckey(&aes, key, key_len);
        if (ret)
                return ret;

        /* Encrypt a block of zeroes - use key area in context */
        memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
        aes_encrypt(&aes, ctx->u.aes.key, ctx->u.aes.key);
        memzero_explicit(&aes, sizeof(aes));

        /* Generate K1 and K2 */
        k0_hi = be64_to_cpu(*((__be64 *)ctx->u.aes.key));
        k0_lo = be64_to_cpu(*((__be64 *)ctx->u.aes.key + 1));

        k1_hi = (k0_hi << 1) | (k0_lo >> 63);
        k1_lo = k0_lo << 1;
        if (ctx->u.aes.key[0] & 0x80) {
                k1_hi ^= rb_hi;
                k1_lo ^= rb_lo;
        }
        gk = (__be64 *)ctx->u.aes.k1;
        *gk = cpu_to_be64(k1_hi);
        gk++;
        *gk = cpu_to_be64(k1_lo);

        k2_hi = (k1_hi << 1) | (k1_lo >> 63);
        k2_lo = k1_lo << 1;
        if (ctx->u.aes.k1[0] & 0x80) {
                k2_hi ^= rb_hi;
                k2_lo ^= rb_lo;
        }
        gk = (__be64 *)ctx->u.aes.k2;
        *gk = cpu_to_be64(k2_hi);
        gk++;
        *gk = cpu_to_be64(k2_lo);

        ctx->u.aes.kn_len = sizeof(ctx->u.aes.k1);
        sg_init_one(&ctx->u.aes.k1_sg, ctx->u.aes.k1, sizeof(ctx->u.aes.k1));
        sg_init_one(&ctx->u.aes.k2_sg, ctx->u.aes.k2, sizeof(ctx->u.aes.k2));

        /* Save the supplied key */
        memset(ctx->u.aes.key, 0, sizeof(ctx->u.aes.key));
        memcpy(ctx->u.aes.key, key, key_len);
        ctx->u.aes.key_len = key_len;
        sg_init_one(&ctx->u.aes.key_sg, ctx->u.aes.key, key_len);

        return ret;
}

static int ccp_aes_cmac_cra_init(struct crypto_tfm *tfm)
{
        struct ccp_ctx *ctx = crypto_tfm_ctx_dma(tfm);
        struct crypto_ahash *ahash = __crypto_ahash_cast(tfm);

        ctx->complete = ccp_aes_cmac_complete;
        ctx->u.aes.key_len = 0;

        crypto_ahash_set_reqsize_dma(ahash,
                                     sizeof(struct ccp_aes_cmac_req_ctx));

        return 0;
}

int ccp_register_aes_cmac_algs(struct list_head *head)
{
        struct ccp_crypto_ahash_alg *ccp_alg;
        struct ahash_alg *alg;
        struct hash_alg_common *halg;
        struct crypto_alg *base;
        int ret;

        ccp_alg = kzalloc_obj(*ccp_alg);
        if (!ccp_alg)
                return -ENOMEM;

        INIT_LIST_HEAD(&ccp_alg->entry);
        ccp_alg->mode = CCP_AES_MODE_CMAC;

        alg = &ccp_alg->alg;
        alg->init = ccp_aes_cmac_init;
        alg->update = ccp_aes_cmac_update;
        alg->final = ccp_aes_cmac_final;
        alg->finup = ccp_aes_cmac_finup;
        alg->digest = ccp_aes_cmac_digest;
        alg->export = ccp_aes_cmac_export;
        alg->import = ccp_aes_cmac_import;
        alg->setkey = ccp_aes_cmac_setkey;

        halg = &alg->halg;
        halg->digestsize = AES_BLOCK_SIZE;
        halg->statesize = sizeof(struct ccp_aes_cmac_exp_ctx);

        base = &halg->base;
        snprintf(base->cra_name, CRYPTO_MAX_ALG_NAME, "cmac(aes)");
        snprintf(base->cra_driver_name, CRYPTO_MAX_ALG_NAME, "cmac-aes-ccp");
        base->cra_flags = CRYPTO_ALG_ASYNC |
                          CRYPTO_ALG_ALLOCATES_MEMORY |
                          CRYPTO_ALG_KERN_DRIVER_ONLY |
                          CRYPTO_ALG_NEED_FALLBACK;
        base->cra_blocksize = AES_BLOCK_SIZE;
        base->cra_ctxsize = sizeof(struct ccp_ctx) + crypto_dma_padding();
        base->cra_priority = CCP_CRA_PRIORITY;
        base->cra_init = ccp_aes_cmac_cra_init;
        base->cra_module = THIS_MODULE;

        ret = crypto_register_ahash(alg);
        if (ret) {
                pr_err("%s ahash algorithm registration error (%d)\n",
                       base->cra_name, ret);
                kfree(ccp_alg);
                return ret;
        }

        list_add(&ccp_alg->entry, head);

        return 0;
}